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[Bug other/50636] GC in large LTO builds cause excessive fragmentation in memory map
- From: "andi-gcc at firstfloor dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 06 Oct 2011 21:46:32 +0000
- Subject: [Bug other/50636] GC in large LTO builds cause excessive fragmentation in memory map
- Auto-submitted: auto-generated
- References: <bug-50636-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50636
--- Comment #5 from Andi Kleen <andi-gcc at firstfloor dot org> 2011-10-06 21:46:32 UTC ---
If it's a 2MB page then madvise MADV_DONTNEED will split it if it's not
2MB aligned. It would be good to optimize the freeing pattern so that this
happens
rarely.
I will try to do some numbers how much 2MB pages improves performance. If yes
we could also do a MADV_HUGEPAGE by default.
But short term fix would be simply to have a threshold for freepages before
freeing?